A group of distinguished former generals today fired a broadside at the British National party (BNP) for using the reputation of the armed forces to its political advantage.

In a letter seen by the Times, the former heads of the army, General Sir Mike Jackson and General Sir Richard Dannatt, and others, said far right groups were "fundamentally at odds" with the values of the British military.

The letter reads: "We call on all those who seek to hijack the good name of Britain's military for their own advantage to cease and desist. The values of these extremists – many of whom are essentially racist – are fundamentally at odds with the values of the modern British military, such as tolerance and fairness."

He told the Times: "The BNP is claiming that it has a better relationship with the armed forces than other political parties. How dare they use the image of the army, in particular, to promote their policies. These people are beyond the pale."

A spokesman for the BNP accused the signatories of the letter of remaining silent about the scandal over MPs' expenses.

He said: "It is rather strange that they said nothing when MPs were embezzling millions of pounds on furnishing their homes whilst our boys were being blown to smithereens because of a lack of funding for equipment."

Griffin is due to appear on the programme alongside the justice secretary, Jack Straw, representatives of the other main parties and the black writer Bonnie Greer.

The generals' letter forms part of a campaign, called Stolen Valour, by leading military figures and Nothing British, an organisation that monitors the BNP. It calls on the Charity Commission to clamp down on BNP organisations masquerading as veterans' charities and calls for legal action to be taken against unauthorised use of photographs.